html,
body {
    height: 100%;
    background-color: #fff;
    margin:0;
}
.content {
   display: flex;
   flex-direction: column;
   align-items: center;
   justify-content: center;
   height: 100%;
}

.content .logo {
    flex:0 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin-top:20%;

}

.content .logo img{
    max-width: 28%;
}
.content .logo .prompt-font{
    color:#01aeff;
    font-size: 22px;
    margin-top:20px;
}

.content .center{
    flex: 1 1 auto;
    width: 100%;
}
.content .bg {
    flex:0 0 auto;
    width: 100%;
}

.content .bg img{
    width: 100%;
}